Parasomnia

Parasomnia
Classification and external resources
ICD-10	F51.3-F51.4
ICD-9	307.47, 327.4, 780.59
eMedicine	med/3131
MeSH	D020447

For the 2008 horror film, see Parasomnia (film)

Parasomnias are a category of sleep disorders that involve abnormal and unnatural movements, behaviors, emotions, perceptions, and dreams that occur while falling asleep, sleeping, between sleep stages, or during arousal from sleep. Most parasomnias are dissociated sleep states which are partial arousals during the transitions between wakefulness and NREM sleep, or wakefulness and REM sleep.

NREM parasomnias

NREM parasomnias are arousal disorders that occur during stage 3 (or 4 by the R&K standardization) of NREM sleep—also known as slow wave sleep (SWS). They are caused by a physiological activation in which the patient’s brain exits from SWS and is caught in between a sleeping and waking state. In particular, these disorders involve activation of the autonomic nervous system, motor system, or cognitive processes during sleep or sleep-wake transitions.^[1]

Some NREM parasomnias (sleep-walking, night-terrors, and confusional arousal) are common during childhood but decrease in frequency with increasing age. They can be triggered in certain individuals by alcohol, sleep deprivation, physical activity, emotional stress, depression, medications, or a fevered illness. These disorders of arousal can range from confusional arousals, somnambulism, to night terrors. Other specific disorders include sleepeating, sleep sex, teeth grinding, rhythmic movement disorder, restless legs syndrome,^{[citation needed]} and somniloquy.

Confusional arousals

With a prevalence of 4%, confusional arousals are not observed very often in adults; however, they are common in children.^[2] Confusional arousals are occasional thrashings or inconsolable crying among children—they are characterized by movements in bed.

Sleepwalking (somnambulism)

Sleepwalking has a prevalence of 1-17% in childhood, with the most frequent occurrences around the age of eleven-twelve. About 4% of adults experience somnambulism.^[3]

Sleep terrors (night terrors)

Main article: Pavor nocturnus

Sleep terror is the most disruptive arousal disorder since it may involve loud screams and panic; in extreme cases, it may result in bodily harm or property damage by running about or hitting walls. Unfortunately, all attempts to console the individual are futile and may prolong or intensify the victim’s confused state. Usually the victim experiences amnesia after the event but it may not be complete amnesia. Up to 3% of adults suffer from sleep terrors, and exhibited behavior of this parasomnia can range from mild to extremely violent.^[4] They typically occur in stage 3 sleep.^[5]

Bruxism (teeth grinding)

Bruxism is a common sleep disorder where the sufferer grinds their teeth during sleep. This can cause sleep disruption for the sufferer and bed partner, wear and fracture of teeth, and jaw pain.

Restless legs syndrome & Periodic Limb Movements

Both of these conditions (RLS and PLM) are classified as dyssomnias according to the DSM-IV. They are considered parasomnias^{[by whom?]}.

REM parasomnias

REM sleep behavior disorder

REM Sleep Behavior Disorder is the most common REM sleep parasomnia in which muscle atonia is absent. This allows the individual to act out their dreams and may result in repeated injury-- bruises, lacerations and fractures-- to themselves or others. Patients may take self-protection measures by tethering themselves to bed, using pillow barricades or sleeping in an empty room on a mattress.^[6] Demographically, 90% of RBD patients are males, and most are older than 50 years of age.^[7]

Typical clinical features of REM sleep behaviour disorder are:

• Male gender predilection
• Mean age of onset 50–65 years (range 20–80 years)
• Vocalisation, screaming, swearing that may be associated with dreams
• Motor activity, simple or complex, that may result in injury to patient or bed-partner
• Occurrence usually in latter half of sleep period (REM sleep)
• May be associated with neurodegenerative disease ^[8]

Acute RBD, occurs mostly as a result of a side-effect in prescribed medication- usually antidepressants.

Chronic RBD is idiopathic or associated with neurological disorders. There is a growing association of chronic RBD with neurodegenerative disorders—Parkinson's disease, multiple system atrophy (MSA) or dementia—as an early indicator of these conditions by as much as 10 years.

Patients with narcolepsy also are more likely to develop RBD.

Recurrent Isolated Sleep paralysis

Catathrenia

Catathrenia, a rapid-eye-movement sleep parasomnia consisting of breath holding and expiratory groaning during sleep, is distinct from both somniloquy and obstructive sleep apnea. The sound is produced during exhalation as opposed to snoring which occurs during inhalation. It is usually not noticed by the person producing the sound but can be extremely disturbing to sleep partners, although once aware of it, sufferers tend to be woken up by their own groaning as well. Bed partners generally report hearing the person take a deep breath, hold it, then slowly exhale; often with a high-pitched squeak or groaning sound.

See also

• Dyssomnia
• Insomnia
• Jactatio capitis nocturna
• Sleep medicine
• Sleep paralysis

References

• Mahowald & Schenck. Insights from studying human sleep disorders. Nature (2005); 437(7063):1279-85.
• Bassetti et al., Lancet (2000); 356: 484–485
• Boeve et al. Journal of Geriatr Psychiatry Neurol 2004; 17:146-157
• Aurora RN et al. Journal of Clincial Sleep Medicine 2010; 6(1):85-95.
• Aurora RN et al. Journal of Clincial Sleep Medicine 2010; 6(4):398-401.

Notes

1. ^ Bassetti et al., Lancet (2000); 356: 484–485
2. ^ Mahowald & Schenck: 1283.
3. ^ Mahowald & Schenck. 1283.
4. ^ Mahowald & Schenck: 1283.
5. ^ Katugampola, M. (2005) Health & Human Development, Pearson Education.
6. ^ Mahowald & Schenck:1284.
7. ^ Mahowald & Schenck :1284.
8. ^ Boeve et al.

Further reading

• Siegel, Ronald (1992). Fire in the Brain: Clinical Tales of Hallucination. 
• Warren, Jeff (2007). The Head Trip: Adventures on the Wheel of Consciousness. ISBN 978-0679314080. 

External links

• Stanford: Parasomnias - Arousal Disorders Information
• Primary Sleep Disorders: Parasomnias
• Psychnet UK
• Insomnia/Parasomnia